Nitrocellulose composition



Patented Jan. 6, 1925.

UNITED STATES PATENT OFFICE.

FRANK J. BOHAN, OF ROCHESTER, NEW YORK, ASSIGNOR TO.EA STMAN'KODAK COM- PAINY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

NITROCELLULOSE COMPOSITION.

No Drawing.

compositions. One object of the invention is to provide a relatively inexpensive composi- I tion from which trans-parent clear coatings may be easily prepared, even under adverse circumstances, which does not require to be heated to secure even evaporation and in which the relative proportions of the ingredients may be considerably varied Without impairing the eflicacy of the composition.

I have discovered that a nitrocellulose composition having the hereinabove recited properties can be prepared b mixing or compounding nitrocellulose with a solvent containing ethyl methylketone, ethyl alcohol and benzol. By way of example, I may prepare a varnish or lacquer by mixing 30% by weight of ethyl methyl ketone with of ethyl alcohol and 50% of benzol. In this mixture I may dissolve 16 ounces of nitrocellulose to each gallon of the solvent. One of the features of my composition is the fact that these proportions may be widely varied, especially as the prices of the difierent ingredients vary. The cheaper ingredients 35 can be considerably increased. when necessary without impairing the usefulness of the product. This is due to the fact that the ethyl methyl ketone, ethyl alcohol and hen-- Applicatioi filed March 22, 1923. Serial No. 626,809.

zol have very nearly the same boilin points and, therefore, evaporate at almost t e same rates, being less than 21? C. apart in boiling point. The composition evaporates evenly and without blooming, or forming opaque coatings, even when the proportions are considerably varied.

Because the vapor tensions of the ingredients are very nearly the same, it is not necessary to raise the temperature above normal room temperature in order to secure an even evaporation at the proper rate. Of course, heating can be used if desired, but it is easier to recover the solvent vapors at the lower vapor tensions correspondlng to the normal temperatures.

My composition does not under ordinary room conditions tend to absorb water in sufficient degree to become hygroscopic and give whitish films.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A composition of matter comprising nitrocellulose dissolved in a mixture of parts of ethyl methyl ketone, 20 parts of ethyl alcohol and 50 'parts by weight of benzol.

2. A composition of matter comprisin nitrocellulose dissolved in a mixture of eth methyl ketone, ethyl alcohol and benzol, t e proportion by weight of each ingredient of the mixture being at least 20% of the weight of said mixture.

Signed at Rochester, New York this 19 day of March 1923.

FRANK J. BOHANp. 

